James, who entered the evening shooting 58.6 percent from the field, was true on 14-of-18 shots and was a nearly perfect 10-of-11 from the free-throw line in the win.
Aiding the Heat's cause was James' sidekick, Dwyane Wade, who put together one of the most complete stat lines we've seen so far this season. In 36 minutes, Wade scored 17 points, dished out eight assists, racked up eight steals and pulled down five rebounds. He also shot 50 percent from the field.
Five Heat players finished in double-figures, including two bench contributors, Norris Cole and Rashard Lewis, each of whom dropped in 11 points.
Dallas stuck around all game long thanks to the offensive stylings of Dirk Nowitzki (28 points on 8-of-12 shooting), but were ultimately undone by 24 turnovers.
Monta Ellis (20 points) and Vince Carter (21 points) each acquitted themselves nicely, but Ellis came up small down the stretch, forcing up a contested three and committing a turnover with under three minutes to go.
Both teams shot better than 50 percent from the field, and the Mavericks actually topped Miami from beyond the arc, hitting on 42.9 percent of their looks from distance.
In the end, though, it was James' cold-blooded shooting that willed the Heat to victory.